A light string includes many bulb assemblies for lightening to display a certain decorative effect. The light string can only be hung without specialty and it is known that it is always provided with a frame, which is patterned. But the light string is hung and winded on the frame without any firm connection. After a period of use, the light string would be usually fallen or loosen from the frame. Hence, the decorative effect is lost.
Accordingly, the present invention is to provide a positioning structure of a frame for engaging with the bulb assembly of a light string in secure and solute the drawback of prior art.